The invention relates to driving units which can be used to rotate shafts, axles, cores, spindles, winding and unwinding mandrels and/or other rotary driven parts. More particularly, the invention relates to driving units of the type wherein a rotary driving member (e.g., a motor-driven shaft) rotates a confining member (e.g., in the form of a wheel) which is pivotable relative to the driving member between an operative position in which the two members cooperate to locate and rotate a driven part and an inoperative position in which the driven part can be removed, detached or withdrawn from torque-receiving engagement with the driving and confining members.
Driving units of the above outlined character are disclosed, for example, in the aforementioned copending patent application Ser. No. 014,938 as well as in German Pat. No. 35 09 108 to Boschert. The patent to Boschert discloses a driving unit wherein the confining member is releasably held in the operative position by a pawl which is pivotably mounted on the confining member and has a pallet arranged to enter a notch in the driving member to be held in such position by a coil spring. An advantage of this driving unit is that the confining member is reliably held in the operative position, even if the driving member is to transmit torque to a heavy and bulky driven part, e.g., to a mandrel or spindle which carries a large supply of convoluted textile or other material. All that is necessary is to employ a relatively strong spring which can oppose movements of the pawl to disengaged position with a requisite force, namely to withstand the action of centrifugal force when the driving unit is in use so that the driving and confining members cooperate to ensure the transmission of torque to a driven part. In order to save space, as well as to ensure that the pawl cannot be accidentally disengaged from the driving member when the latter is rotated to transmit torque to a driven part, the pawl is normally placed within the confining member so that it does not protrude beyond the outline of the confining member when the driving member rotates. The arrangement is such that the force which is required to disengage the pallet of the pawl from the driving member must be supplied practically exclusively by the fingers of the operator, i.e., the fingers must overcome the resistance which the aforementioned spring offers to movement of the pallet to disengaged position. The patent to Boschert does not disclose or suggest any means for mechanically moving the pawl to and from the position of engagement with the driving member. In fact, it would be rather difficult to devise acceptable disengaging means which would not extend well beyond the outline of the wheel-shaped confining member. The outwardly protruding disengaging means would be likely to be actuated by a careless person while the driving unit is in use, to injure a person standing next to the driving unit and/or to interfere with the operation of a lifting mechanism which is employed to transfer heavy and bulky driven parts into and from engagement with the driving and confining members.
German Pat. No. 31 27 553 to Kunz discloses a modified driving unit with an auxiliary device serving to move the confining member to and from operative position. A drawback of such auxiliary device is that it projects well beyond the outlines of the driving an confining members so that the operators must exercise great care during insertion of a driven part into or during withdrawal of a driven part from the socket of the driving member. It has been found that the loading and unloading mechanism is likely to damage the auxiliary device which is used to move the confining member between its operative and inoperative positions.
Additional driving units are disclosed in German Pat. No. 917,592 to Fazis (this patent does not disclose any means for moving the confining member to its inoperative position), in U.S. Pat. No. 4,344,304 to Eiche (which discloses cushions and centering means for the driven part), in U.S. Pat. No. 4,460,134 to Kunz (which discloses a mechanism for adjusting a portion of the reeling shaft), and in U.S. Pat. No. 3,147,985 to Hornberger (this patent discloses a driving chuck wherein the socket for an end portion of a spindle is designed to automatically guide the end portion to an optimum position for reception of torque from the driving member).